CBSE > Class 10 > Science | CBSE Board | Homework Help

18 Elements in the modern periodic table are arranged in 7 periods and 18 groups. The number of vertical columns in the modern periodic table is 18. Vertical columns in the table are called groups.

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Ayan Ali 5 years, 1 month ago

The number of vertical columbs in the modern periodic table is 18. And vertical column in the table are called groups

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find out how the sewage in your locality is treated are there mechanism in place to ensure the local water bodies are not polluted by untreated sewage

Posted by Sri Harshitha 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Sewage can be treated close to where the sewage is created, which may be called a "decentralized" system or even an "on-site" system (in septic tanks, biofilters or aerobic treatment systems). Alternatively, sewage can be collected and transported by a network of pipes and pump stations to a municipal treatment plant.

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Why soap not form micelle in ethanol

Posted by Shanky Pandit 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Yogita Ingle 5 years, 1 month ago

A molecule of soap has two dissimilar ends. At one end is the hydrocarbon chain which is water repellent. At the other end carboxylate anion is present which is water soluble end. When soap is dissolved in water, many molecules come together and form a group called micelle, these micelles are formed because their hydrocarbon chains come together and the polar ends are projected outward. Micelle formation in ethanol will not occur because the hydrocarbon chain end of the soap will also dissolve in water.

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Meghna Thapar 5 years, 1 month ago

A molecule of soap has two dissimilar ends. At one end is the hydrocarbon chain which is water repellent. At the other end carboxylate anion is present which is water soluble end. ... Micelle formation in ethanol will not occur because the hydrocarbon chain end of the soap will also dissolve in water.

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Why is a handspan or foot not used as a standard unit of length

Posted by Harsha Shreya 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Foot steps and hand-spans are not the ideal or standard unit of length because these are not accurate. Even though one can measure using his body parts but these are not universal measurements. The size of body parts of different people vary. Different measures will lead to confusion so that is why we have chosen a unique standard measuring unit of length as to prevent these confusions.

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Write a balanced equation for a chemical reaction that can be characterized as precipitation

Posted by Sonia Atom 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Precipitation is the condensation of the atmospheric water.
Mixing barium chloride with copper sulphate, a formation of white sulphate of copper chloride is formed.
This forms to be double displacement reaction where the sulphate ions are displaced by chloride ions and vice versa accordingly.
Na₂SO₄ + BaCl₂→ BaSO₄ + 2 NaCl

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What is placenta . Mention it's role during pregnancy

Posted by Jasmeet Singh 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Shaily Sharma 5 years, 1 month ago

The placenta is an organ that develops in your uterus during pregnancy. This structure provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. The placenta attaches to the wall of your uterus, and your baby's umbilical cord arises from it.

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Yogita Ingle 5 years, 1 month ago

The placenta is a flattened structure found int the uterus of a pregnant women. It provides nourishment to the developing foetus and at the same time carries waste generated by the foetus out to be excreted.

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How to ditact gas

Posted by Anmol Singla 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Lakshay Sangwan 5 years, 1 month ago

Which gas? Hydrogen.... We have a burning candle and place the burning candle near the bubbles . Hydrogen gas burns with pop sound

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Does concave mirror forms virtual object?

Posted by Robins Kumar 5 years, 1 month ago

CBSE > Class 10 > Science

5 answers

Shikha Gupta 5 years, 1 month ago

Offcourse yes.... Concave mirror also produces virtual and erect images......put an object between focus point and pole and you will observe an image behind the mirror which is both virtual and erect.?

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Nishu Atrish 5 years, 1 month ago

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Yogita Ingle 5 years, 1 month ago

Convex mirrors always produce a virtual, erect and diminished image and the decrease in size of image depends on the position of the object in front of the mirror.

Plane Mirrors always produce a virtual and erect image having the same size as that of the object irrespective of the position of object.

Concave mirrors produce real and virtual, erect and inverted, diminished, same-sized and magnified image depending upon the position of the object on the principal axis. But the concave mirror forms a virtual image only when the object is placed between the Focus and the pole of the mirror but the image is magnified (enlarged).

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Zero Two Friend Debbarma 5 years, 1 month ago

Not object it should be image

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Amit Kumar 5 years, 1 month ago

Yes

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What is gold leaf experiment

Posted by Robins Kumar 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Vacuum tube experiments concluded that electrons, protons and neutrons are the fundamental particles of all atoms. Many hypothesis and experiments were proposed to know the distribution of these fundamental particles inside the atom. Thomson suggested a model of the spherical atom with positive charge distributed over the entire volume and electrons placed on it like plums on a cake. Rutherford tried to determine the structure of the atom experimentally.

Rutherford in 1911, carried out an experiment called ‘Gold foil experiment’ and could conclude the nature of an atom and the position of the protons present in the atom decisively. He also proposed the position and behaviour of electrons. They bombarded fragile sheets of gold foil with fast-moving alpha particles. Alpha particles, a type of natural radioactive particle, are positively charged particles with a mass about four times that of a hydrogen atom.

Observation of the experiment

Most of the alpha particles were indeed undeflected, a tiny percentage (about 1 in 8000 particles) bounced off the gold foil at extensive angles. Some were even redirected back toward the source.

Conclusion of the experiment

He concluded that all the positive charge and the majority of the mass of the atom must be concentrated in a minimal space in the atom’s interior, which he called the nucleus. The nucleus is the tiny, dense, central core of the atom and is composed of protons and neutrons.

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Archamadis principle

Posted by Jatin Op 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Archimedes’ principle states that: “The upward buoyant force that is exerted on a body immersed in a fluid, whether partially or fully submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the center of mass of the displaced fluid”.

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Define right- hand thumb rule

Posted by Francis Lalu 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Knowledge Singh 5 years, 1 month ago

It state that "Put the thumb of your left hand along the direction of current passing through the conductor and then wrappe the finger around the conductor which shows the direction of magnetic field of the conductor".

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Who is Maxwell corkcrew

Posted by Francis Lalu 5 years, 1 month ago

CBSE > Class 10 > Science

3 answers

Shikha Gupta 5 years, 1 month ago

Maxwell is an excellent scientist who give the theory of identifying the way and direction of magnetic field lines around a straight current carrying conductor..... This experiment is also called as.. "Maxwell's right hand thumb rule"?

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Yogita Ingle 5 years, 1 month ago

The Maxwell's Screw Rules
The Maxwell Screw Rules sometime is also called the Maxwell's Corkscrew Rule. Imagine a right handed screw being turn so that it bores its way in the direction of the current in the wire. The direction of rotation gives the direction of the magnetic field.
<a href="http://bp0.blogger.com/_PyvjcvYfRLk/SFnpDf4Eg3I/AAAAAAAAAEY/z4sb_G5DYkw/s1600-h/Maxwell-Screw-Rule.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"></a>

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Knowledge Singh 5 years, 1 month ago

Maxwell was a great Science, who gave us "Right hand thumb rule".

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What is the difference between breathing and respiration

Posted by Prashansa Rai 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Prashansa Rai 5 years, 1 month ago

Thank you so much

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Yogita Ingle 5 years, 1 month ago

Breathing	Cellular Respiration
Definition
Breathing involves the process of inhaling oxygen and exhaling carbon dioxide	Cellular respiration is the process of breaking down of glucose to produce energy, which is then used by cells to carry out the cellular function.
Process Occurrence
Breathing takes place in the lungs. Also involves the nose, mouth and pharynx	Respiration takes place in cells
Type of Process
Breathing is voluntary as well as an involuntary physical process. (For example, breathing during sleep is involuntary. Voluntary breathing is observed when we sing, speak, swim or for relaxation techniques)	Respiration is an involuntary chemical process.
Production of Energy
There is no production of energy in this process.	Energy is produced and released in the form of ATP.
Cellular Activity
As it occurs outside cells, it is called the extracellular process. (Occurs between the organism and the external environment)	As it occurs inside cells, it is called the intracellular process.

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How to find period and group of an element in a periodic table

Posted by Kirpajot Kaur 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

If the atomic number is given from the electronic configuration we can find the poasition of the element.

Example:

Carbon (6)

Electronic configuration: (2,4)

No. of valence electrons gives the group number and no of shells gives period.

So it corrosponds to group 4 and period 2.

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Define recombination of prism

Posted by Francis Lalu 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 5 years, 1 month ago

Recombination Prism is the prism which enables the recombining of the dispersed ray of light (VIBGYOR) into the ray of white light.

The bending of light or the refraction phenomenon is used to disperse a white light into VIBGYOR by first prism and the recombination prism due to its optical arrangement recombines VIBGYOR into the white light which was originally incident n the first prism.

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Why Mendel chose pea plant for his experiment

Posted by Ramneek Kaur Brar 5 years, 1 month ago

CBSE > Class 10 > Science

3 answers

King Adithya H M... 5 years, 1 month ago

Gregor Mendel conducted hybridization experiments on around 29,000 pea plants. Peas were an ideal choice for Mendel to use because they had easily observable traits there were 7 of which he could manipulate. ... He took years of breeding constant family lines to perfect the original constant traits.

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Yogita Ingle 5 years, 1 month ago

The reason for the selection of pea plants for the genetic experiments are

Easy to grow in the garden.
The flowers of pea plants are hermaphrodite, i.e flowers have bisexual characteristics.
Easy to obtain pure breed plant through self-fertilization
The generation time of pea plants is less.
They have excellent disease resistance and have an optimal rate of survival.

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Vaishu ? 5 years, 1 month ago

Mendal choose pea plant because they grow up within short duration of time and so that he can study more about generations quickly.They were also easily available. Also pea plants have many different characteristics like dwarfness, tallness , different colours of pea,etc.

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1.Which of the statements about the reaction below are incorrect?2PbO(s) + C(s) ® 2Pb(s) + CO2(g)(a)Lead is getting reduced.(b)Carbon dioxide is getting oxidised.(c)Carbon is getting oxidised.(d)Lead oxide is getting reduced.(i)(a) and (b)(ii)(a) and (c)(iii)(a), (b) and (c)(iv)all

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Sanchita Prakash 5 years, 1 month ago

a and b

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Vaishu ? 5 years, 1 month ago

(i) (a) and (b) is answer.

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2. Define the unit of current. Ans. SI unit of electric current is Ampere. Current is said to be 1 ampere, if 1 coulomb charge flows per second across a cross-section of conductor. 3. Calculate the number of electrons constituting one coulomb of charge. Ans. Charge on one electron = 1.6 x 10-19coulomb. No of electron in one coulomb of charge = 1/1.6 x 10-19 = 6.25 x 1018 electrons. Page No. 202 1. Name a device that helps to maintain a potential difference between across a conductor. Ans. Battery 2. What is meant by saying that the potential difference between two points is 1 v? Ans. The potential difference between two points is said to be 1 volt, if 1 joule of work is to be done for moving charge of 1 coulomb from one point to another. 3. How much energy is given to each coulomb of charge passing through a 6-volt battery? Ans. Potential difference (V) = 6 V Charge (Q) = 1 C Energy = total work done (W) = Q x V = 1x6 = 6 joule. Page No. 209 1. On what factor does the resistance of a conductor depend? Ans. The resistance of a conductor depends on i. length of conductor (l) ii. Area of cross-section (A) iii. Temperature iv. Nature of material used to make conductor 2. Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why? Ans. The current flows more easily through a thick wire as compared to thin wire of the same material, when connected to the same source. It is due to the reason that resistance increases with decrease in thickness. 3. Let the resistance of an electric component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it? Ans. It is given that resistance R of the electrical component remains constant but the potential difference across the ends of the component decreases to half of its value. Hence, as per Ohm’s law, new current also decreases to half of its original value. 4. Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal? Ans. Coils of electric toasters and electric irons are made of an alloy due to the following reasons: i. Resistivity of an alloy is generally higher than that of pure metal. ii. At high temperature, an alloy does not oxidize readily. Hence, coil of an alloy has longer life. 5. Use the data in Table 12.2 to answer the following: (a) Which among iron and mercury is a better conductor? (b) Which material is the best conductor? Ans. (a) Iron is the better conductor than mercury. (b) Silver is the best conductor because its resistivity is the least. Page No. 213 1. Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V, each, a 5 Ώ resistor, 8 Ώ resistors and a 12 Ώ and a plug key, all connected in series. Ans. The schematic diagram of circuit is as follows: 2. Redraw the circuit of question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the 12 Ώ resistors. What would be the reading in the ammeter and voltmeter? Ans. Here ammeter A has been joined in series of circuit and voltmeter V is joined in parallel to 12 ohms’ resistor. Total voltage of battery V = 3x2 = 6 V. Total resistance R = R1+ R2+ R3 = 5 Ω +8 Ω +12 Ω = 25 Ω Ammeter reading (current) = I = V/R = 6/25 = 0.24 A. Voltmeter reading = IR = 0.24 x 12 = 2.88 V.

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

King Adithya H M... 5 years, 1 month ago

Thanks for giving Question & Answer

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Vaishu ? 5 years, 1 month ago

Thanks for your question+ answer

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ANSWER

1. What does an electric circuit mean? Ans. An electric circuit is a continuous and closed path of an electric current. If the electric circuit complete, current can flow through the circuit.

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

5 answers

King Adithya H M... 5 years, 1 month ago

Thanks for giving Question & Answer

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Vaishu ? 5 years, 1 month ago

?? phir padhaai koi nahi karta .

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Akhya Sahay 5 years, 1 month ago

Kaash boards m v tmhare hi jaisa ques pucha jata... Ques k sath ans attached ??

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Vaishu ? 5 years, 1 month ago

? What is this answer is already given in Question?? ?

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Yogita Ingle 5 years, 1 month ago

A continuous and closed path of an electric current is called an electric circuit. An electric circuit consists of electric devices, source of electricity and wires that are connected with the help of a switch.

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The substances that undergo chemical change in the reaction (1.1), magnesium and oxygen, are the reactants. The new substance is magnesium oxide, formed during the reaction, as a product.

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

3 answers

Vaishu ? 5 years, 1 month ago

Ya, Magnesium ribbon burn with dazzling white light to give white substance called magnesium oxide.

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Ritika Ritika 5 years, 1 month ago

Yes

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Kumari Shalini 5 years, 1 month ago

Yaa right.... It's correct

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How to draw dot structure of Hcl molecule??

Posted by Kumari Shalini 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Aryan Dargan??? 5 years, 1 month ago

Cl will share one electron with H.

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Vaishu ? 5 years, 1 month ago

Sorry unable to upload image here.

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ANSWER

CaSO.12HO+112HOCaSO.2HO42242(PlasterofParis)Gypsum)

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Kumari Shalini 5 years, 1 month ago

Your way of writing the question is really very strange... I am unable to understand what you have written here... I don't think your chemical formula of gypsum and plaster of paris is correct... Please write your questions carefully...

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You already know that acids are sour in taste and change the colourof blue litmus to red, whereas, bases are bitter and change the colour ofthe red litmus to blue. Litmus is a natural indicator, turmeric is anothersuch indicator. Have you noticed that a stain of curry on a white clothbecomes reddish-brown when soap, which is basic in nature, is scrubbedon it? It turns yellow again when the cloth is washed with plenty ofwater. You can also use synthetic indicators such as methyl orange andphenolphthalein to test for acids and bases.

Posted by Rishabh Pawar 5 years, 1 month ago

CBSE > Class 10 > Science

1 answers

Kumari Shalini 5 years, 1 month ago

Yes, you have written correct statement regarding the change of indicators in acidic and basic nature..

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What is the ph value of dilute ethaonic acid

Posted by Nandini Soni 5 years, 1 month ago

CBSE > Class 10 > Science

2 answers

Kumari Shalini 5 years, 1 month ago

The pH value of dilute ethanoic acid is approximately 3 .... Which is less than seven making it acidic in nature...

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Yogita Ingle 5 years, 1 month ago

The pH of dilute solutions of hydrochloric acid, ethanoic acid and lemon juice is less than 7 and therefore, they are acidic in nature.

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A 52-year old near-sighted person wears eye-glass with a power of -5.5 dioptres for distance viewing. His doctor prescribes a correction of +1.5 dioptres in the near-vision section of his bi-focals. This is measured relative to the main part of the lens (i) What is the focal length of his distance-viewing part of the lens? (ii) What is the focal length of the near-vision section of the lens? (5 Mark question)

Posted by Vidhya Vijay Baskar 5 years, 1 month ago

CBSE > Class 10 > Science

0 answers

ANSWER

What is a balance chemical equation

Posted by Sonia Atom 5 years, 1 month ago

CBSE > Class 10 > Science

3 answers

Kumari Shalini 5 years, 1 month ago

A chemical equation that has equal number of atoms in reactant side as well as product side, is called a balanced chemical equation...

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Hidha Nazrin 5 years, 1 month ago

if the atomic number of reactant and product are equally balanced type of chemical equations are called balanced chemical equations...hope u can understand

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Mamta ... 5 years, 1 month ago

A balanced chemical equation is an equation that have equal numbers of each type of atom on both sides of the arrow......hope this helps uhh?

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What is fertilization?

Posted by Balram Sharma 5 years, 1 month ago

CBSE > Class 10 > Science